I have a pretty short commute(5km) and live in Halifax but with some good thermal underwear, gloves, jacket I was able to ride all winter except for about 20 days. On 23 mm slicks too but I'm getting something better this winter.
Ottawa-Gatineau area, in my case. The downtown areas can often be clear of snow/ice, but not if you're on the outskirts. In this case it isn't the gear so much as the tire width.
Gear makes a big difference.